From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E09D2C433EF for ; Thu, 5 May 2022 08:17:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347463AbiEEIU6 (ORCPT ); Thu, 5 May 2022 04:20:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346977AbiEEIUY (ORCPT ); Thu, 5 May 2022 04:20:24 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C7D749688 for ; Thu, 5 May 2022 01:16:45 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 4AF8C210DF; Thu, 5 May 2022 08:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1651738604; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=97UDNK1f7czhnU/2ak2EMjgJM9WmcipgW6hepwuQnLg=; b=TIGROP5NtrO/PMKocRwXDq4uW8i352wOc1Z8dfJPBykWG1KVaUs1y2V2ugsyPQNmx7HW7A 7YEaBEYBaDKYEspokFV4o5IqKEomEss+SP90j3p4SJQhRp2HPvh7OngYWLnofHdSf1J4/b gKvNZ3TxKDt4H8fjI3G6ZJ0tlhzkvPg= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 1CCDA13B11; Thu, 5 May 2022 08:16:44 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 8JqSBeyHc2K1BwAAMHmgww (envelope-from ); Thu, 05 May 2022 08:16:44 +0000 From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini Subject: [PATCH v3 02/21] xen/grant-table: never put a reserved grant on the free list Date: Thu, 5 May 2022 10:16:21 +0200 Message-Id: <20220505081640.17425-3-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220505081640.17425-1-jgross@suse.com> References: <20220505081640.17425-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Make sure a reserved grant is never put on the free list, as this could cause hard to debug errors. Signed-off-by: Juergen Gross --- V3: - new patch --- drivers/xen/grant-table.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 6ea31ea26008..1a1aec0a88a1 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -207,6 +207,10 @@ static inline void check_free_callbacks(void) static void put_free_entry(grant_ref_t ref) { unsigned long flags; + + if (unlikely(ref < GNTTAB_NR_RESERVED_ENTRIES)) + return; + spin_lock_irqsave(&gnttab_list_lock, flags); gnttab_entry(ref) = gnttab_free_head; gnttab_free_head = ref; -- 2.35.3